Hepatitis A is a vaccine-preventable, communicable disease of the liver caused by the hepatitis A virus (HAV). The infection is transmitted via the fecal-oral route, usually from direct person-to-person contact or consumption of contaminated food or water. Hepatitis A is an acute, self-limited disease that does not result in chronic infection. HAV antibodies (immunoglobulin G [IgG] anti-HAV) produced in response to HAV infection persist for life and protect against reinfection; IgG anti-HAV produced after vaccination confer long-term immunity. This report supplants and summarizes previously published recommendations from the Advisory Committee on Immunization Practices (ACIP) regarding the prevention of HAV infection in the United States. ACIP recommends routine vaccination of children aged 12–23 months and catch-up vaccination for children and adolescents aged 2–18 years who have not previously received hepatitis A (HepA) vaccine at any age. ACIP recommends HepA vaccination for adults at risk for HAV infection or severe disease from HAV infection and for adults requesting protection against HAV without acknowledgment of a risk factor. These recommendations also provide guidance for vaccination before travel, for postexposure prophylaxis, in settings providing services to adults, and during outbreaks.